[Lain]

I just can't for the life of me think of what 'Gnome Keys' could mean.
Google only returns stuff about GNOME's Keyring (linux thing) which is more or less useless given that's all modern cryptographically secure tech like RSA/AES and this should be able to be done by hand without me needing to run XOR's on the whole string after I get done converting it to ASCII numbers smh.

My next best guess would be GNome as in viGeNere cipher, but I have a ten letter ciphertext and a bunch of text that's either longer or shorter, and even if I were to run everything through Vigenere against the ciphertext, there's no guarantee I'd find anything. And given that, like I mentioned, CSE likely doesn't want to hire based off luck, there must be some sort of way to interpret the clue and come up with the proper key.
And yes, I've tried 'gnome/gnome keys' as a key with Vigenere. No, it did not work. I've also tried using the Badge text as a key, and that doesn't do much especially given how much longer it is than the ciphertext, making it another unlikely candidate for a key.

It probably does have something to do with the Badge text as a key, given they mentioned it in the clue and how the badge itself also has a key in the middle. But how the hell I interpret that is completely beyond me.

EDIT: Came up with something cool:

Code:

G = 7
N = 14
O = 15
M = 13
E = 5

Correspond those to positions in the Badge text and you get MATRI (Latin word for Mother)
Unfortunately, doing the same thing with KEYS gives you 'PITU' which is not a Latin word, nor is MATRIPITU or anything like that. But it's a new key that I can use with previous algos I've tried.

EDIT 2:
MATRI does not work as a key for anything, whether it be anything I tried above, or Vigenere.
None of the other words in the hint, when looked up in the table, have any sense or significance, just GNOME (and arguably KEYS).
Perhaps it refers to "matri"ces, using something like a hill cipher or some other polygrammic.
I really hope it doesn't, because I have no idea how I'm going to find the matrix needed in this puzzle.

EDIT 3:
I gave the hill cipher a shot. No luck.
Since typically hill ciphers use 2x2 matrices (or four values, in other words,) I found the only place in the whole puzzle that had four numerical values: the lengths of the words in the crest (7 8 2 8.)
Since I didn't know how to arrange them, I tried both:
[7 8]
[2 8]
and
[7 2]
[8 8]

Which both respectively ended up with the bigrams [G, K] and [W, A] for the first two letters of the ciphertext UT (using the alphabet of a=0, z=25)
If a=1, z=26 is used, you get [F, J] and [V, Z] which both wouldn't make a word, so I figured the second matrix would work.
But alas, for the next bigram of BO, I got [J, Q], so WAJQ was going to be my message, which again doesn't make a word.
Tragic.

This puzzle is giving me an aneurysm so I'm gonna get some actual schoolwork in and head to bed soon.
Spies are something else, man.

EDIT 4: One more before the Eternal Worm Devours Connecticut
Since I kept thinking about matrices and some linear algebra practice, I went ahead and tried using NUNTIUMCOMPARATETCUSTODIT as a 5x5 matrix to multiply a 5x2 matrix containing my presumed ciphertext UTBOHUGKFR, as so:

Code:

ALPHABET: A=0, B=1, [...], Z = 25

[13 20 13 19 08]    [20 20]    [975 741]          [13 13]   [N N]
[20 12 02 14 12]    [19 06]    [910 766]          [00 12]   [A M]
[15 00 17 00 19]  X [01 10]  = [450 793]  % 26  = [08 13] = [I N]
[04 19 02 20 18]    [14 05]    [849 620]          [17 22]   [R W]
[19 14 03 08 19]    [07 17]    [894 857]          [10 25]   [K Z]

So nothing useful.
Glad I can at least get the practice in for matrix multiplication.
I'm using pen+paper for all this still because I want to adhere close to the rules of the challenge instead of cheating, because if I cheat I'll finally be free of this curse but I won't be satisfied with how I arrived at the answer. I know there are calculators online for this kind of stuff, but I'm not gonna have that privilege on my exams either.

I'm starting to think that another one of my assumptions may have been wrong, presumably the one where I assume that it's all about the first letters. There are ten words, yes, but that doesn't mean that I need to pull every first letter out of them. Perhaps the last, or the second. Probably not the last either, because the first three characters would be "EEE" in that case, and no English (Latin-derived) word has three of the same letter in a row (but that could reinforce the idea of using that rotational cipher thing to get the answer.)

Perhaps gnome keys could refer to gnome characters, i.e. characters that when lowercase would be short. If that was the case, then writing the clue as a normal sentence would be:

Use the badge of honour until gnome keys first reading.

Removing capitalization would change the first character to a U instead of S.
Highlighted in red would be the letters I'd choose, but the ones highlighted in green could also fall under the definition of a 'short' letter, noting how G goes below the 'floor' and I only has a little dot that goes over, and doesn't go all the way up.
In this case, FIRST READING would be interpreted to the first occurrence of such letters. Which also makes sense, because OF only has one such occurence, so I cannot find the 'second' occurrence there, or anything beyond the first.

But, alas, the clue was given in all-caps (in a pretty font which is also irrelevant according to host) so I doubt this would be the answer either.
Also note how many double-letters there are (you get even more when you use the lookup table(s)). ROT ciphers/Caesar ciphers aren't of much help either.
I'm just throwing ideas around like crazy.